The power supply wiring of a semiconductor integrated circuit generally includes a mesh-style wiring structure. The I/O cell of the semiconductor integrated circuit is located on the periphery of the chip. The power coming from the exterior pad, through the I/O cell, is supplied to the interior mesh-style power supply wiring network. At each interior point in the semiconductor integrated circuit, the interior cell receives and consumes the power coming from the power supply wiring network. Because power is consumed at each interior point in the semiconductor integrated circuit, the voltage of the power supply wiring network diminishes as it nears the center of the chip. In other words, the voltage of the power supply wiring network is higher on the periphery of the semiconductor integrated circuit and becomes lower as it nears the center. This may be undesirable in many applications.
To avoid this, many current methods control the power supply wiring network voltage drop by widening the power supply wirings and increasing the number of the I/O cells that supply power from the exterior source. Other methods employ a power circuit, installed at a right angle to the mesh-style power circuit, to avoid the imbalance of voltage supply caused by spatially uneven consumption of power.